Processes for producing isothiazole derivatives

A method for producing a 3-halo-1,2-benzisothiazole represented by the general formula (III), characterized by reacting a 1,2-benzisothiazole represented by the general formula (II):

• ##STR7## wherein R.sup.2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, or a carboxyl group or an ester thereof,
• with a halogenating agent to give a 3-halo-1,2-benzisothiazole represented by the general formula (III):
• ##STR8## wherein X represents a chlorine atom or a bromine atom;
• and R.sup.2 has the same definition as R.sup.2 in the general formula (II).

A method for producing a 3-halo-1,2-benzisothiazole represented by the general formula (III), characterized by

• treating a 2-(alkylthio)benzaldehyde oxime represented by the general formula (I):
• ##STR9## wherein R.sup.1 represents an alkyl group having 1 to 4 carbon atoms;
• and R.sup.2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom,
• with a halogen compound to give a 1,2-benzisothiazole represented by the general formula (II):
• ##STR10## wherein R.sup.2 has the same definition as R.sup.2 in the general formula (I);
• and
• reacting the obtained 1,2-benzisothiazoles with a halogenating agent to give a 3-halo-1,2-benzisothiazole represented by the general formula (III):
• ##STR11## wherein X represents a chlorine atom or a bromine atom;
• and R.sup.2 has the same definition as R.sup.2 in the general formula (II).

A method for producing a 1-(1,2-benzisothiazol-3-yl)piperazine represented by the general formula (V), characterized by

• treating a 2-(alkylthio)benzaldehyde oxime represented by the general formula (I):
• ##STR12## wherein R.sup.1 represents an alkyl group having 1 to 4 carbon atoms;
• and R.sup.2 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a nitro group, a carboxyl group or an ester thereof, or a halogen atom,
• with a halogen compound to give a 1,2-benzisothiazole represented by the general formula (II):
• ##STR13## wherein R.sup.2 has the same definition as R.sup.2 in the general formula (I);
• reacting the obtained 1,2-benzisothiazoles with a halogenating agent to give a 3-halo-1,2-benzisothiazole represented by the general formula (III):
• ##STR14## wherein X represents a chlorine atom or a bromine atom;
• and R.sup.2 has the same definition as R.sup.2 in the general formula (I);
• and
• reacting the 3-halo-1,2-benzisothiazoles with a piperazine represented by the general formula (IV):
• ##STR15## wherein R.sup.3 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a substituted alkylene group having 1 to 6 carbon atoms, to give a 1-(1,2-benzisothiazol-3-yl)piperazine represented by the general formula (V):
• ##STR16## wherein R.sup.2 has the same definition as R.sup.2 in the general formula (I);
• and R.sup.3 has the same definition as R.sup.3 in the general formula (IV).